Method and apparatus for sealing cartons



July 27, 1965 w, SAIDEL 3,196,758

METHOD AND APPARATUS FOR SEALING CARTONS Filed April 11, 1963 i l /46 6 J0 4 14. 64 mvf on MWKSW 0&7, F/Z/ wmWQ.

United States Patent 3,196,758 METHUD AND APPARATUS FUR SEALKNG CARTON William R. Saidel, Park Forest, Ill., assignor to Integral Packaging (l'ompany, Chicago Heights, 11]., a corporation of lllinois Filed Apr. 11, 1963, Ser. No. 272,273 6 (Jlaims. (CI. 9336) The present invention relates to a novel method and apparatus for processing folding cartons or other articles, and more specifically to a novel method and apparatus for securing portions of an article or carton in a closed or assembled relationship.

While it will be apparent that certain features of the present invention may be adapted for processing various articles or carton structures, the present disclosure will be facilitated by specifically describing a method and apparatus especially suitable for closing and heat sealing one or more ends or side structures of a folding carton. It is contemplated that the car-ton shall have an end or side structure comprising a plurality of overlapping panels or flaps and thermoplastic coating or adhesive material disposed on such panels or flaps so that a portion of the coating material is on an outer surface of an outermost panel or flap for enhancing the appearance of the carton or for serving a moisture or similar function while another portion of the thermoplastic material is disposed between the panels or flaps for adhesively securing the panels or flaps together.

It is an important object of the present invention to provide a novel method and apparatus for heat sealing carton structures of the above described type or other articles in a relatively rapid and effective manner for promoting more economical processing of the cartons.

A further important object of the present invention is to provide a novel method and apparatus for heat sealing cartons for use of the above described type in a rapid and effective manner while preventing fouling of the apparatus by the portion of the adhesive or coating material on exposed outwardly facing surfaces of the carton.

A more specific object of the present invention is to provide a novel method and apparatus for processing cartons of the above described type or other articles by applying heat and pressure to predetermined areas thereof for securing overlapping portions or flaps together and for subsequently promoting cooling of at least a portion of the heated adhesive or coating material while maintaining pressure on limited areas of the carton in a manner which prevents sticking of the carton to the apparatus or folding of the apparatus with the adhesive or coating material.

Gther objects and advantages of the present invention will become apparent from the following description and the accompanying drawings where-in:

FIG. 1 is a fragmentary simplified perspective View showing an apparatus incorporating features of the present invention;

MG. 2 is a fragmentary plan view of a carton blank which may be processed in accordance with features of the present invent-ion;

FIG. 3 is an enlarged fragmentary perspective view showing the carton blank in a partially assembled condition;

FIG. 4 is an enlarged fragmentary perspective view showing portions of the apparatus of FIG. 1 for applying heat and pressure to a side or end structure of a carton.

FIG. 5 is an enlarged fragmentary sectional view taken generally along lines 5-5 in FIG. 4; and

FIG. 6 is an enlarged fragmentary sectional view taken generally along lines 66 in FIG. 4.

Referring now more specifically to the drawings wherein like parts are designated by the same numerals through- Bdhhflfi Patented July 27, 1%65 'ice out the various figures, a carton 10 of a type which is adapted to be processed in accordance with features of the p esent invention is formed from a blank l2 of suitable fiberboard or other sheet material. The carton is provided with rectangular bottom and top panels 14 and 16, respectively, and side panels 18 and 26. A fiap 22 extends from the end panel 21%), which flap is adapted to extend over and to be secured adhesively or otherwise to the panel 16 when the carton blank is folded to its assembled position as shown in FIGS. 1 and 3.

The carton is provided with opposite end structures, only one of which is shown. These opposite end structures are identical to each other, and as shown best in FIGS. 2, 3, 5 and 6, each end structure includes an inner fiap 24 articulated along a scored bend line to the panel 14, and an outer flap 26 articulated along another scored bend line to the panel 16. Relatively small end fiaps 28 and 3d are articulated to the end of the side panels 18 and Ztl. When the carton is folded to its fully assembled condition, the small flaps or tabs 23 and 34} extend within the flap 24 as shown best in FIG. 3 and the flap 26 is folded downwardly over the flap 24 as shown best in FIGS. 5 and 6.

It is contemplated that the entire surface of the blank 12 may be covered with a coating 32 of a material adapted to give the carton the desired finished appearance, moisture-proofness, grease resistance or other characteristics.

t is further contemplated that the material of the coating 32 is preferably a thermoplastic composition which may also function as an adhesive for securing the flaps 2446 of the end structures with respect to each other. Reference is made to pending application Serial No. 177,162, filed March 5, 1962, for a full disclosure of a composition which may be used.

As shown best in FIGS. 5 and 6, one portion 34 of the adhesive or coating material is disposed between the flaps 2426 for securing these flaps together while another portion 3-6 of the adhesive or coating material ex tends over the outwardly facing and exposed surface of the flap 26 for providing the desired outside appearance or characteristics. The thickness of the adhesive material is exaggerated in FIGS. 5 and 6 in order to facilitate the illustration thereof.

In accordance with a feature of the present invention, an apparatus 38 shown in simplified form in FIGS. 1 and 46 is provided for processing successive cartons 1d and more specifically for closing and sealing the opposite end structures of the cartons. The apparatus 38 comprises conveyor members 4th for advancing successive cartons along a predetermined path of travel. The conveyor members 40 may be in the form of endless members such as belts or chains or, if desired, they may be in the form of reciprocating members adapted to advance the cartons with an intermittent step-by-step motion. Upwardly extending projections or dogs 42 or other suitable means are provided on the conveyor members 48 for engaging and positively advancing the cartons.

It is contemplated that the carton blank 12 will initially be partially assembled by folding the panels 16 and 18 over and substantially flat against the panels 14 and 2t) and then folding the panel or flap 22 over and securing it to the panel 16. The carton blank may then be shipped or stored in its flat partially folded and assembled donditionv Thereafter the carton may be folded to its fully assembled condition by hand, but preferably the apparatus 38 is provided with a folding mechanism, schematically indicated as 44 in FIG. 1, adjacent the conveying means for setting up and folding successive carton blanks to a finally folded or assembled condition. This folding mechanism may be of various known constructions and therefore need not be described in detail, and it suffices to state that the mechanism is such that each carton blank is initially opened from its aforementioned flattened condition so that the panels 14 and 16 are spaced apart whereupon the flaps 23 and 30 of the end structures are folded inwardly to a position shown in FIG. 3, the panels 24 of the end structures are folded upwardly and against the flaps 28 and 30 and the panels 26 of the opposite end structures are finally folded downwardly over and against the flaps of panel 24. Furthermore, the mechanism 44 may be such that it is adapted to process successive blanks while the blanks or cartons are either continuously or intermittently advanced along the predetermined path of travel by the conveying means.

The apparatus 38 is provided with means for heat sealing the opposite end structures of successive cartons moving along the conveyor members 44). This means comprises a pair of elongated bars 46 and 48 respectively associated with electrical heating elements St The bars 46 and 48 are disposed for engaging and applying suitable pressure to opposite ends of the cartons whereby to press the outer flaps 26 of the structures against the inner flaps. At the same time the bars 4-6 and 48 are heated by the electrical elements 50 or other suitable means for heating the elements of the opposite end structures of successive cartons.

The heating action of the bars 46 and 43 causes the portion 34 of the coating or adhesive material between the panels or flaps 24- and 26 of each end structure to be heated and activated for adhesively securing these panels together. At the same time the outer portion 36 of the adhesive or coating material is, of course, heated and softened. In order to prevent the softened portions 36 of the coating material from building up either on the carton or on the bars 46 and 48 as the cartons pass along the bars, grooves 52 are formed in the faces of the bars 46 and 48 for scraping any buildup or excess material from the passing cartons and directing such material downwardly to a suitable receptacle or trough 54 beneath each of the bars. The grooves 52 are constructed and arranged so that they extend diagonally downwardly from adjacent upper margins of the bars and rearwardly with respect to the direction of movement of the cartons.

Before the adhesive connection between the panels or flaps 24- and 26 of each end structure is completed and fully effective, it is necessary to cool the portions 34 of the adhesive material between these flaps. At the same time the apparatus is constructed for maintaining the pressure on the outer flaps 26 so as to insure intimate engagement with the inner flaps during the cooling of the adhesive material. During cooling of the portions 3 of the adhesive material the outer portions 36 also are cooled, In accordance with an important feature of the present invention the apparatus is constructed for cooling of the adhesive material while preventing the outer portions 36 of the material from either sticking to or fouling the apparatus.

Immediately downstream of the path of travel of the cartons from the heating and pressure bars 56 and 4-8, the apparatus is provided with additional guide elements or pressure bars 56 and 58. These bars are also heated by electrical elements 60 or other suitable means. However, the bars 56 and 58 are constructed so as to present narrow edges 62 for contact with the opposite end structure of the cartons. Thus the portions of the adhesive material which contact the edges 62 are heated so as to avoid sticking to the bars 56 and 58. At the same time the areas of the adhesive material 36 which are not engaged by the bars 56 and 58 are exposed to the air for cooling. In addition, the areas of the flaps 26 and the portions 34 of the adhesive material which are offset from the narrow edges 62 are exposed to the surrounding atmosphere for cooling prposes. As shown in the draw ings, the edges 62 are quite narrow as compared with the overall Width of the panels 26 so that there will be suflicient portions of the adhesive 34 ofiset from the edges 62 which will be cooled for providing an adequate connection between the panel 26 and 24 immediately after the cartons pass beyond the bars 56 and 58. Of course, after the cartons pass beyond the bars, the remainder of the adhesive material will cool for obtaining a permanent secure connection between the end flaps. Preferably the bars 56 and 58 are constructed and arranged so that their edges 62 engage the flaps or panels 26 at a location between the upper and lower margins of the panels 26 for promoting intimate contact of the panels 26 throughout their height with the inner panels and for enabling portions of the adhesive material along opposite margins of the panels to cool.

In order to promote more rapid cooling of the adhesive material and to insure a sufiiciently secure connection between the panels of the end structures when the cartons pass beyond the bars 56 and 58, nozzles 64 and 66 are positioned along opposite sides of the path of travel of the carton for directing blasts of cooling air along the opposite end structures of the cartons while the end structures are engaged by the bars '56 and 53. The nozzles 64 and 66 may be associated with individual blowers 63 and 79 or they may be connected with any other suitable source of air. As shown best in FIG. 6, the bars 56 have an angular construction providing a depending wall 72. The wall 72 forms a batlle which channels at least a portion of the air from a nozzle along and adjacent carton end structure for promoting more effective cooling of the end structure.

A brief resume of the method of processing cartons and the like in accordance with the present invention is as follows: The cartons are first folded manually or with suitable folding mechanisms for positioning flaps or panels of end structures in overlapping relationship, which flaps or panels have their outwardly facing surfaces substantially covered with a coating and adhesive composition. Then the cartons are advanced along a predetermined path of travel. While the cartons are disposed along this path of travel, heat is applied over substantially the entire area of the end structures and the outermost flaps or panels of the end structures are pressed against the innermost flaps or panels. The application of heat is directed from outside of the end structures whereby the heat penetrates the outermost flaps or panels of the end structures and adhesive material thereon and the adhesive material between the inner and outer flaps or panels of the end structures for activating the adhesive material. Then upon further advancement of the cartons along the panel the pressure and heat are maintained on relatively narrow longitudinally extending bands of the end structures while portions of the end structures offset from such bands are cooled sufficiently to enable the adhesive material between the panels or flaps of the end structures to maintain the panels in assembled relationship. Thereafter, the pressure on the end panels is removed and all of the adhesive material is cooled.

While the preferred embodiment of the present invention has been shown and described herein, it is obvious that many details may be changed Without departing from the spirit and scope of the appending claims.

The invention is claimed as follows:

1. An apparatus for securing an end structure of a carton including overlapping inner and outer flaps and a coating of thermoplastic adhesive material between said flaps and on an outer surface of said outer flap, said apparatus comprising means for advancing said carton along a predetermined path of travel, a heatable bar, first heating means associated with said bar for heating said bar, said heatable bar being disposed adjacent said carton advancing means and having a predetermined width in a direction extending upwardly along a side of said path of travel for engaging said outer flap and pressing the outer flap against the inner flap and heating the adhesive material both between said flaps and on said outer surface, and a second heatable bar disposed adjacent said means downstream of said path of travel from said first 5 bar, second heating means associated with said second bar for heating said second her said second bar presenting an edge elongated lengthwise of said path of travel and having a narrow width in said direction as compared with s id first bar for engaging a narrow band of said outer flap for holding said outer flap against said inner flap while exposing portions of said outer flap and said adhesive material offset from said edge for cooling.

2. An apparatus, as defined in claim El, which includes means disposed adjacent said first mentioned means for directing a flow of cooiing air along said edge and against an outer flap of the carton being engaged by said edge for promoting cooling or" said portions of said outer flap and adhesive material offset from said edge.

.1. An apparatus, as defined in claim 2, which includes means e2: ending along said edge and offset therefrom providing a channel for directing a portion of said air along said edge and against said outer flap.

d. An apparatus as defined in claim It, which includes diagonally extending groove means on said first mentioned bar for removing any excess building up of heated adhesive material from said outer flap while the carton is being advanced along said first mentioned bar.

5. An apparatus, as defined in claim 1, wherein said second mentioned bar is disposed for presenting its edge at a location intermediate upper and lower margins of said outer flap of a carton moving along said path of travel.

6. A method of sealing a carton having a side structure including overlapping inner and outer flaps and a coating of thermoplastic adhesive material between said flaps and on an outer surface of said outer flap, comprising continuously acvancing said carton along a predetermined path of travel, applying heat and pressure to an outer side of said outer flap for ressing said outer flap against said inner flap and for heating and activating the adhesive material between said flaps and on said outer surface, subsequently engaging said outer flap with narrow heated means and applying heat and pressure with said narrow means to a relatively narrow band of the outer side of said outer fiap while continuously advancing the carton along said path of travel while cooling portions of said outer flap and said adhesive material odset from said band sufficiently for adhesiveiy connecting said flaps together, and subsequently cooling all of the adhesive ma terial.

References Cited by the Examiner UNITED STATES PATENTS 1,586,375 5/26 Metcalf 53-388 2,357,786 9/44 Wells 156-498 X 2,587,422 2/52 Wills 156583 2,823,729 2/58 Stickelber 53-388 2,871,772 2/59 Nelson 93--49 X 2,912,908 11/59 Crane et a1. 93-52 FRANK E. BAILEY, Primary Examiner. 

1. AN APPARATUS FOR SECURING AN END STRUCTURE OF A CARTON INCLUDING OVERLAPPING INNER AND OUTER FLAPS AND A COATING OF THERMOPLASTIC ADHESIVE MATERIAL BETWEEN SAID FLAPS AND ON AN OUTER SURFACE OF SAID OUTER FLAP, SAID APPARATUS COMPRISING MEANS FOR ADVANCING SAID CARTON ALONG A PREDETERMINED PATH OF TRAVEL, A HEATABLE BAR, FIRST HEATING MEANS ASSOCIATED WITH SAID BAR FOR HEATING SAID BAR, SAID HEATABLE BAR BEING DISPOSED ADJACENT SAID CARTON ADVANCING MEANS AND HAVING A PREDETERMINED WIDTH IN A DIRECTION EXTENDING UPWARDLY ALONG A SIDE OF SAID PATH OF TRAVEL FOR ENGAGING SAID OUTER FLAP AND PRESSING THE OUTER FLAP AGAINST THE INNER FLAP AND HEATING AND THE ADHESIVE MATERIAL BOTH BETWEEN SAID FLAPS AND ON SAID OUTER SURFACE, AND A SECOND HEATABLE BAR DISPOSED ADJACENT SAID MEANS DOWNSTREAM OF SAID PATH OF TRAVEL FROM SAID FIRST BAR, SECOND HEATING MEANS ASSOCIATED WITH SAID SECOND BAR FOR HEATING SAID SECOND BAR SAID SECOND BAR PRESENTING AN EDGE ELONGATED LENGTHWISE OF SAID PATH OF TRAVEL AND HAVING A NARROW WIDTH IN SAID DIRECTION AS COMPARED WITH SAID FIRST BAR FOR ENGAGING A NARROW BAND OF SAID OUTER FLAP FOR HOLDING SAID OUTER FLAP AGAINST AND INNER FLAP WHILE EXPOSING PORTIONS OF SAID OUTER FLAP AND SAID ADHESIVE MATERIAL OFFSET FROM SAID EDGE FOR COOLING. 